Telegraph regenerative repeater



Jan. 9, 1934. E. P. BANCROFT TELEGRAPH R EGENERATIVE REPEATER Filed Feb.6, 1932 2 Sheets-Sheet 1 FIG. 3

INVENTOR ERWIN P. BANCROFT BY 60/ ATTORN Jan. 9, 1934. E, BANCRQFT1,942,588

TELEGRAPH REGENERATIVE] REPEATER Filed Feb. 6, 1932 2 Sheets-Sheet 2INVENTOR ERWIN R BANCROFT BY f ATTORN Y Patent No. 1,229,201.

Patented Jan. 9, 1934 UNITED STATES PATENT OFFICE i,942, 5 ss TELEGRAPHREGENERATIVE REPEATER Erwin 1?. BancrofLBrooklyn, Y., assignor, toInternational Communications Laboratories, Inc., Newark, N.J., acorporation of New York Application February 6, 1932. SerialNc. 591,324

5 Claims. (o1.'178 70) My invention relates to improvements inregenerative repeaters in which a single set of elements is used toregenerate successively the individual elements of each signal.

The device may be used to regenerate signals in start-stop systems andin systems in which ing drawings, wherein:

Fig.1 shows a start-stop regenerative repeater;

Fig.2 shows a repeaterin which continuous synchronism and correction ismaintained; and

Fig. 3 shows the differential gearing in connection with the corrector.I

In Figsl and 2 the transmitting ,stationiis representedfatX and isequipped with the usual transmittercomprising a distributor of the typewell known in the art and it is not thought necessary to illustrate themechanism. The station ..Y is equipped with the usual printer mechanismwhich responds to the retransmitted impulses and it is not thoughtnecessary to illustrate such mechanism.

Referring to Fig. 1, shaft 5 carrying a toothed .cam 4 is arranged .tomake one revolution for 35,

each received code signal. Shaft 5 is started and stopped under controlof impulses preceding and following each code signal by any suitablemeans such, for example, as the well known start-stop clutch mechanismdescribed in United States Patent No. 1,205,248, or the single magnetmechanical distributor disclosed in United States Power for operatingthe shaft may be furnished from any suitable source, such as a constantspeed electric motor or the like.

, The teeth on cam 4 are arranged at definitely spaced intervals aroundthe circumference .of the cam and correspond in number to the impulsesof each code signal, including the start andstop impulses. It isarranged to be driven in synchronism with the incoming signals, Oneshort segment (or the stop position) is sfuchthat the length of timerepresentedby the short segment, plus the normal stop time of the shaft,represents one signalling impulse.

Lever3 pivoted at 13 is arranged to be oscillated by cam 4 through theaction of a tooth 15 carried ,by lever 3 and"a spring 3. A bifurcatedlever 2 is pivoted on the lever 3 opposite the pivot end 13 andoscillates with lever 3. A pin 12 carried by lever'2 slides in a slot 11inthe end of armature 10f relaylO. Armature 1 is pivotedat 1'. Relay 10is shown schematically polar relay, such as is shown in Fig. 2.

Located adjacent and immediately above the bifurcated ends of lever 2 isa three-arm lever 6 pivoted at 14. One arm 18 of lever 6 carriescontacts which are arranged to make contact with stationary contacts 7or 8. A jockey roller as a neutral re laybut may be replaced by a 9,mounted adjacent the end of contact'arm 18,

serves to hold the latter in contact with which ever contact, 7 or 8, itis placed upon. Lever '2, through the medium of pinl2,' isfar'ranged tobe rocked into either of the two'positions of armature 1 of relay 10. V

The bifurcated ends 19 and 20 of lever 2 are so arranged" with respectto arms 16 and 1'7 of lever 6 that in either its right or left handpolsition only one arm of lever 2 will contact with the correspondingarm of lever 6,as lever 2 is moved upward by lever 3. Thus, if armature1 is in its left-handor attracted position, as shown, arm "20 of lever 2will be opposite arm 1'7 of lever 6.

With the partsin this position, lever '6 will be rotatedcounter-clockwise by lever 2,as the latter is raised as cam erotates.Contact will thus be closed. When armature 1 is moved to its right-hand,position, under the influence of spring 6, lever 2 will move to theright and arm 19 Under this condition, when lever 2 wise, therebyopening contact 7 and closing contact 8.

The operation is as follows:

The mechanism is shown in the stop or rest position. The arrival of thestart impulse from station X will operate relay 10 and armature 1 willmove to the right, thereby bringingarm 19 of lever 2 opposite arm 16. Atthe same, time the clutch mechanism will be released, allowing shaft 5to rotate. A tooth on cam 4 immediately lifts lever 3, causing lever 2to rotate lever'6 about its pivot to open contact '7 and close contact8, and the retransmitted or regenerated impulse is sent to station Y.Lever 3 immediately returns to its rest position, leaving lever 2 free,to,be positioned by armature 1' in accordance with the first impulse ofthe code signal. When lever 2 has been positioned by armature 1, lever 3is again raised by the next tooth on cam 4 and lever 6 either remains incontact with contact 6 or is moved to make contact with contact '7,depending upon whether the first impulse of the code signal is spacingor marking, respectively. The remaining impulses of the code signal actin a similar manner to position lever 6 in contact with contact 7 or 8in accordance with the marking and spacing conditions corresponding toeach impulse. Since cam 4 rotates under local control in synchronismwith the incoming signals, lever 6 will be moved from contact '7 tocontact 8, or vice versa, in definite time relation corresponding to theindividual impulses of the code signals, and in this way the latter willbe repeated into line 2 completely regenerated.

Referring now to Fig. 2, a bifurcated lever 22, pivoted to a lever 23and 26, is oscillated in definite time relation by means of a toothedcam 24 carried by a shaft 56 driven at a constant speed and maintainedin synchronism with the incoming signals, as will be explained later.Lever 22 is also under control of the armature 21 of a relay 40, whosewinding 41 is connected with the line over which the signals arereceived. Lever 22, under the dual control of the toothed cam 24 andrelay 40, serves to position a three-arm lever so as to cause arm 38thereof to make contact with either contact 27 or 28 in accordance withthe polarity of the signals received. The operation of this portion ofthe mechanism is the same as that already described in connection withFig. 1.

Stops 45 and 46 on either side of the armature 21 of relay 4O serve ascontacts to complete a circuit for magnet 50. The circuit may be tracedfrom the battery 44, through the current limiting resistance 49, contact45, armature 21 of relay 40, condenser 47, magnet 56 to ground. With thearmature in the right-hand position, as shown, the circuit may be tracedfrom ground through contact 46, armature 21, condenser 47, magnet toground. The arrangement of this circuit is such that, each time thearmature 21 makes contact with either contact 45 or 46, an impulse willbe transmitted through magnet 50 to attract its armature 54 momentarily.Thus, when armature 21 makes contact with contact 45, condenser 47 willbe charged and armature 54 of magnet 50 momentarily attracted. Whenarmature 21 next makes contact with contact 46, condenser 47 willdischarge through magnet 50, again momentarily attracting the armature54.

The toothed cam 61, exactly like the toothed cam 24 on shaft 56', servesto oscillate armature 54 at right angles to the core of magnet 50through the medium of a lever 55 pivoted at 62, the armature 54 beingpivoted to arm 55 at 43. If armature 54 is in the retracted position, asshown, when it is raised by a tooth of cam 61, nothing happens. If,however, armature 54 is attracted by the magnet 50 at the time it israised, it will contact with an arm 66 of a bell crank pivoted at 6'7,rotating the same in a clockwise direction. The other arm or" the bellcrank 65 carries a pawl 68 pivoted at 69 adapted to engage a ratchetwheel 70 mounted concentric with the shaft 56. Rotation of the bellcrank 65 in the clockwise direction will cause the pawl 68 to pass overand engage a new tooth on the ratchet wheel 76, so that when the pawl'71 of lever 55 passes over a tooth of the cam 61 and returns to itsnormal position, the ratchet wheel '70 will be turned a oscillation oflever 55 to which armature 54 is distance of one tooth in a clockwisedirection under the influence of spring 57. The wheel '10 is retained inits new position by a jockey roller or holding pawl, not shown.

The apparatus is assumed to be driven by a constant speed motor such,for example, as a phonic wheel motor (not shown) whose shaft 60 (Fig. 3)carries a gear 59. Arranged to engage gear 59 is a second gear 51carried by shaft 58, which also carries a third gear 52. Gear 52 isadapted to engage gear .53 carried by shaft 56. The gear ratios, 59 and51, and 52 and 53, are such that shafts 6i] and 56 are driven atslightly different speeds. In the arrangement shown, shaft 56 is assumedto be rotating at a slightly higher speed than shaft 60. Shaft 58, towhich gears 51 and 52 are rigidly attached, is journaled in bearings(not shown) carried by the ratchet wheel 76. It will thus be seen that,if ratchet wheel '75 rotated in a clockwise direction about shaft 56 asa center, shaft 56 will be advanced with respect to shaft 60.

In multiplex systems, in which mechanical correction is employed, it iscommon practice to rotate the receiving distributor either slightlyfaster or slightly slower than the transmitting distributor. It isfurther usual to generate the impulses for correcting the phase positionof the receiving distributor from the signals through a system of relaysand electrical circuits. In the repeater shown in Fig. 2, the receivingdistributor is arranged to normally rotate slightly slower thansynchronous s eed. Under this condition shaft 56 will gradually fallbehind its proper synchronous position. When it has fallen sufiicientlyfar behind the synchronous position to allow 59 to attract armature 54in time to cause it to engage the arm 66 of bell crank 65, the ratchetwheel '20 will he stepped ahead, advancing shaft 56 to its propersynchronous position. The correction is under the dual control of theincoming signals, since magnet 50 is energized each time relay armature21 changes position and the receiving distributor which controls thepivoted. It will thus be seen that, although the shaft 56 tends to fallbehind the true synchronous position, its phase position will becorrected as soon as it has fallen far enough behind for armature 54 toengage lever 66, and it will thereby be maintained in synchronism withthe incoming signals.

In order for the signals to be properly regenerated, it is necessary forthe cam 24 to be positioned in definite time relation with respect tothe incoming signals. Although no means is shown for adjusting therelative phase relation of the cams 61 and 24, a differential gearingcan be employed and when so used the cams 24 and 61 will be mounted onseparate shafts coupled by this diiferential gearing. Such anarrangement is shown in United States Patent No. 1,543,119 of June 23,1925.

What is claimed is:

1. In a regenerative repeater, the combination of a relay for receivingsignals, a rotatable cam, a movable arm, a plurality of contacts, meanscontrolled by the relay for positioning said arm in relation to saidcontacts, means controlled by the cam for operating said arm to causethe operation of the contacts with which it is positioned, means forcreating a momentary impulse at each reversal of the received signals, alever movable transversely under control of the momentary impulse, localmechanism controlling longitudinal movement of said lever, and meansoperated by said lever under such dual control to maintain said cam insynchronism with the received signals.

2. In a regenerative repeater, the combination of a relay for receivingsignals, a set of contacts, a rotatable cam, means controlled by saidcam for operating said set of contacts for retransmitting signalscorresponding to the received signals, means controlled by said relayfor creating a momentary impulse at each reversal of the receivedsignals, a lever movable both laterally and longitudinally, one movementthereof being under control of the momentary impulse and the other undercontrol of said local mechanical mechanism, and a correcting deviceoperated by said lever under such dual control for maintaining said camin synchronism with the received signals.

3. In a regenerative repeater, the combination of a relay for receivingsignals, means controlled by said relay for creating a momentary impulseat each reversal of the received signals, a set of contacts, a rotatablecam, means controlled by said cam for operating said set of contacts forretransrnitting signals corresponding to the received signals, a locallyoperated second cam, a lever movable both laterally and longitudinally,one movement thereof being under control of the momentaiy impulse andthe other under control of said second cam, and a correcting deviceoperated by said lever under such dual control for maintaining said camsin synchronism with the received signals.

4. In a regenerative repeater, the combination of a relay for receivingsignals, a set of contacts, a rotatable cam, means controlled by saidcam for operating said contacts for retransmitting signals correspondingto the received signals, a shaft on which said cam is mounted, a secondcam mounted on said shaft, a lever movable both laterally andlongitudinally, one movement thereof being under control of themomentary impulse and the other under control of said second-mentionedcam, a ratchet wheel fixed to said shaft, a lever pivoted intermediateits ends and having at one end thereof a pawl for engaging the teeth ofsaid ratchet and having its other end positioned to be engaged by saidfirst-mentioned lever when moved both laterally and longitudinally undersuch dual control thereby to tilt said pivoted lever to cause the pawlto step back and engage a succeeding tooth of the ratchet, and means forcausing the pivoted lever to return to normal position and move theratchet wheel.

5. In a regenerative repeater, the combination of a relay for receivingsignals, a set of contacts, a rotatable cam, means controlled by saidcam for operating said contacts for retransmitting signals correspondingto the received signals, a shaft on which said cam is mounted, a secondcam mounted on said shaft, a lever movable both laterally andlongitudinally, one movement thereof being under control of themomentary impulse and the other under control of said secondmentionedcam, a ratchet wheel fixed to said shaft, a lever pivoted intermediateits ends and having one end thereof positioned to be engaged by'saidlaterally and longitudinally movable lever whilst under said dualcontrol, and a pawl carried by the other end of said pivoted lever forengaging said ratchet wheel to effect a corrective movement thereofthereby to maintain said cams in synchronism with the received signals.

ERWIN P. BANCROFT.

